OutdoorKing Repair Forum Forums Repairs and Maintenance Questions on Walk Behind Lawn Mower Frames Question On Scott Bonnar Cylinder Mowers Drive Sprocket Question

Hi guys, I am currently restoring an old Rover Thoroughbred, parts are pretty hard to find for this so I am trying to substitute a few SB parts where necessary..

The drive sprocket is completely worn down.. I've never seen a sprocket so badly worn
So I am trying to see if the sprocket for a scott bonnar can be made to fit.

I believe the part number is A453990

Cheers

Hello jmadden91

A warm welcome to these forums.

Yes, parts for thoroughbreds are getting thin.
That's a shame because it was a solid, competent design.

So, you are talking about the small drive sprocket at the top.
I'm hoping a member will be able to help here.
I guess the main issue is internal diameter and number of teeth.
https://www.outdoorking-forum.com.au/index.p...th=1_17_346_348_394&products_id=5233

If all else fails, an off-the-shelf sprocket from a bearing
company might be an option.

Hope this helps.
-------------------------
Jack

If the tooth count is the same, and it appears to be from the pictures, and the pitch is the same, then you can probably make the rest fit with some turning on a lathe as long as the internal diameter is not already larger. Then it would get a bit tricky making a sleeve. Have you checked against other Rover products? The Rancher Autodrive ride ons have a couple of similar sprockets in the final drive, perhaps something there will fit?

Perfect, thanks for the advice guys. Tooth count is the same, ill take it down to a few mower shops etc when they open back up and see if I can find something similar.

Cheers

Here you go.
http://www.ebay.com.au/itm/MOTOR-DRIVE-SPROCKET-FITS-17-ROVER-AND-SCOTT-BONNAR-CYLINDER-MOWERS-/171165967145?hash=item27da496329:g:L9YAAOSwAKxWaPWL

Hi aussietrev, unfortunately that is the 12 tooth top sprocket for the Scotty Model 45 and the Rover 45....essentially the same machine...not the Rover Thoroughbred which is the machine this member has.
Many thanks for your help tho.

It has the part number he listed, A453990, I guess he got that mixed up.

Hi aussietrev, yes mate, that appears to be the case as the OEM part number is 9855-0.

I realise its for the scott bonnar guys, thats the question. The part for the thoroughbred isn't available anywhere I can find, so I am hoping to retrofit the scott bonnar sprocket to the thoroughbred.

Deejay do you happen to know the shaft diameter of the scott bonnar sprocket?

You can get a whole mower cheap here if you happen to be near Queanbeyan.
http://www.ebay.com.au/itm/rover-thoroughbred-14-cylinder-mower-/221974312434?hash=item33aeb335f2:g:hbYAAOSwcBhWW~yi

Deejay, that worn down sprocket is a 12 tooth, unless I am having trouble counting. Is the thoroughbred less or more teeth?

The thoroughbred is 12 tooth, the scott bonnar is also 12tooth